Well and method of constructing and cementing same



J. W. ALLEN May 18, 1937.

WELL AND METHOD OF CONSTRUCTING AND CEMENTING SAME Fil ed Sept 12, 19s;

Junentor attornegs Patented May 18, 1937 NlTED STATES PATENT OFFICE WELLAND METHOD OF CONSTRUCTING AND CEMENTING SAME 8 Claims.

The present invention relates to drilled wells such as water or oilwells, gas wells, artesian wells and the like and more particularly to acement or concrete pipe (or casing) therefor and to the method ofconstructing same.

In such wells as conventionally constructed there is usually providedametallic pipe of from two to six inches, more or less, in diameterextending substantially the length of the bore of the well, which boremay vary from one hundred feet or less to several thousand feet. Suchpipe, or casing as it generally termed, is employed in the transmissionof fluid (gas, water or oil) from the well. It is generally necessary,particularly in the upper portion of the well, also. to use a metalliccasing of a diameter slightly smaller than the earth bore of the well,to serve as a support preventing the sides of the well from caving in,this being in addition to the pipe or casing first above described.These metallic pipes and casings are expensive particularly in thelarger sizes where the price often runs several dollarsv per foot ofeasing.

It has long been customary to use cement mixtures for coating the sidesof dug wells, by which is meant those wells of a diameter sufiicient toallow a man to descend into them to do the necessary plastering of thewell sides. But, because of the impossibility of such method being usedin the case of drilled wells, due to their small bore, steel casing orpipe has always been used and considered the only means to accomplishthe end in view-namely, to support the sides of the well andto provide asuitable passageway' for the gas or fluid from the well.

One of the objects then, of this invention is to provide a practicalmethod by which concrete or cement may be used in lieu of the customarypipes and casings.

To the attainment of this object, a removable form is provided; a meansof holding the form in center of the well so that the walls will be ofuniform thickness is suggested; a means of placing the concrete orcement so that no porous cavities will result, is utilized; meansproviding for the removal of the form, means for drying and curing theconcrete, and means for treating the surface so as to make it moreimpervious to water, oil or gas and thereby increase its usefulness andlasting qualities, are contemplated. The method by which this isaccomplished will appear as the description proceeds, in which referenceis made to the accompanying sheet of drawings in which:

Figure 1 is a vertical longitudinal section through the bore of the welljust prior to the construction of a cement or concrete pipe therein, andshowing apparatus used in carrying out the method;

Figure 3 is a similar view showing the cement or concrete pipeimmediately after being poured;

Figure 3 is a similar view showing the cement or concrete pipe afterremoval of the temporary metallic form;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure 5 is an enlarged fragmentary longitudinal section illustratingdetails of the form and the medium between the form and outer edge ofthe well.

In describing my method and the well structure resulting therefromspecific reference will be made to the accompanying sheet of drawings inwhich like reference numerals designate like parts.

When the bore I0 is drilled and it has been ascertained what size offinished opening is desired in the well, a hollow tubular form, whichhas been previously coated externally with a suitable meltable materialM, which issolid at normal well temperatures, such as asphalt, paraflln,heavy grease, sulphur or the like, is lowered into the well; This formis of such a size that the external diameter of the coated form,including the coating, will be the same as the desired diameter 22 ofopening in the finished well, and is of suflicient length to extendsubstantially from the top to the bottom of the well. Ordinary casing orpipe is practical for the form. It is necessary that the coatingmaterial have a low melting point but be solid at ordinary welltemperature and said coating be of uniform thickness and of suflicientthickness to extend slightly beyond all raised places on the form, suchas conplings, etc. If desired, the couplings may be of a kind to goinside the form or casing.

While reasonably straight in actual practice, drilled wells and moreespecially deep wells, deviate more or less from the vertical,- nor is along string of pipe perfectly straight, so that a string of pipe whenlowered into the well, though much smaller than the bore of the well,may at one depth come in contact with one side of the well, and at alower depth be in the center of the bore, and-at a still lower depthtouch the opposite side, possibly for a distance of many feet.

To overcome this difliculty and to serve certain other purposes as willappear there are secured about the form, externally of the asphalticcoating, and at suitably spaced intervals a series of spacing collarsit, of metal, or any long lasting material subject to use in concrete orcement construction. They have a diameter less than the bore of the welland a curved under-surface as shown in Figure 1, so as not to impedelowering of the form into the well. As shown by Figure 4, hollowcircular openings extend vertically through these spacing collars so asto allow free passage of the concrete or cement. Also if it is necessaryto use reinforcing rods H! or other equivalent means for strengtheningthe cement or concrete these spacing collars [6 will form a convenientmeans of securing same, by placing reinforcing rods through the holesmade for that purpose inthese collars, as illustrated in Figures 1 and 4and, if thought necessary, annular sections of perforated or expandedmetal may be used and secured to the spacing collars. The collarillustrated contains four openings for cement passage and four'forreinforcing rods but these collars may be constructed with more or lessholes and only with openings for cement passage where no reinforcingrods are used. Use of the collars will tend to prevent formation of thinspots when cement is subsequently poured about the form.

When the form I2 is in position cement or concrete in a liquid orsemi-liquid state will be forced down thru the inside of the form by anyconventional pressure apparatus so as to flow out at the bottom of theform and be caused to fiow upwardly within the annular space between theform and the walls of the well l0 to the top of the well. The cementremaining within the form can be displaced in any convenient manner asby forcing sufiicient fluid under pressure down the form to drive theconcrete out and thereafter lowering the form slightly to the bottom ofthe well shutting off all communication between the interior of the formand the space outside to prevent flow of cement or concrete back intothe form. In deep wells where the opening within the, form issufliciently large a smaller pipe 20 as shown in Figure 1 may be usedfor forcing the concrete thru to the bottom of the well following thesame method as above. The purpose of forcing the cement or concrete in aliquid or semiliquid state to the bottom of the well and causing it torise to the top around the form is to prevent the formation of airpockets and insure a solid formation. However in certain wells,particularly shallow wells, it may be possible where the space betweenthe form and sides of the well is sufficient and the cement used issufficiently liquid to introduce the cement or concrete into the annularspace from the top and insure a solid formation void of air pockets.Also where conditions permit the cement or concrete may be introducedthrough a pipe running from top of the well to bottom between the formand sides of the well which may be gradually withdrawn as the well isfilled, this latter method preventing any necessity of the cementeverentering the inside ,of the form.

Any suitable arrangements may be made in pump wells for seating pumpcylinders and in artesian, gas or oil wells for drilling through thefinal distance or plug after the concrete has set and necessaryarrangements at bottom and top of well for controlling as well asarrangements for placing a strainer' pipe at the bottom of the well maybe made.

The cement or concrete will flow up through and around the spacingcollars l6 and the reinforcing, if any is used, to completely enclosesame and they will remain embedded in the concrete.

Thereafter steam is introduced into the form l2 to help cure the cementor concrete, and cause the asphaltic coating on the outside of the formto. melt. This will release the form from the concrete, and the materialwill tend to coat and penetrate the concrete, thus greatly aiding inmaking same impervious to water, oil or gas to serve the double purposeof lengthening its life by protecting it from direct contact with water,oil or gas as well as preventing any loss of products from the well byseepage through the concrete or cement. Any suitable heating medium suchas hot air, hot water or electric heating device may be used for thesame purpose as the steam.

The asphaltic substance having melted around the form, the form can nowbe withdrawn leav-v ing the completed concrete or cemented well readyfor the transmission of gas, oil or water as the case may be, throughthe bore 22, and the single concrete casing thus will take the place ofboth metallic casings used in prior practice.

Aside from the great saving in cost over the conventional use of metalcasing and metal pipe, another important feature is, that in thosesections of the country Where at present periodic replacement of metalcasing is required, due to metallic corrosion, this method ofconstructing a cement or concrete pipe in the well will do away withreplacement expense, as concrete becomes stronger with age.

Wherever the term cement is used Portland cemen is suggested, though anyother type of cement might be used if suitable, but what is known towell men as cement grout, will probably be most desirable; It iscontemplated, that if desired such chemical reagents as calcium chlorideor calcium oxychloride may be used in the cement mixture where Portlandcement is used to hasten hardening and increase early strength, thoughin deep wells it will probably not be desirable except where theparticular conditions are such as to recommend it. Arrangement may bemade to slightly alternately raise and lower the coated form while thecement is being forced into the well to aid in securing a solid andimpervious cement formation.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. The method of constructing concrete or cement pipe in drilled wellsfor the transmission of fluid from within the earth to the surface whichcomprises coating a tubularform externally with a meltable substancewhich is solid at ordinary temperatures, drilling a well bore of greaterdiameter than the form, positioning the said coated form within saiddrilled bore and in evenly spaced relation to the walls thereof, forcinga cementitious substance into the space between said form and sides ofthe well from the bottom of the well upwardly, heating said form to adegree sufiicient to melt said substance with which the form is coated,and releasing the form from the cement, and withdrawing said form.

2. The method of constructing wells which comprises coating a tubularform externally with a meltable substance which becomes hardened atordinary temperaturesdrilling a well bore of greater diameter than theform, positioning said coated form within said bore and in spacedrelation to the walls thereof, forcing a cementitious substance into thespace between said form and walls, heating said form to a degreesufficient thereof by said meltable substance, by heating said form to adegree suflicient to melt said substance and release the form from thecement, and withdrawing said form, thereby leaving a cement casinghaving a fluid impervious bore.

4. The method of constructing wells which comprises coating a tubularform externally with a meltable substance which is solid at ordinarytemperatures, drilling a well bore of greater diameter than the form,applying to said form a spacing collar, and securing a reinforcingmember to said collar, positioning said coated form,

collar and reinforcement within said bore whereby said collar willmaintain the form in spaced relation to the walls of the bore, forcing acementitious substance into the space between said form and walls,heating said form to a degree suflicient to' melt said substance andrelease the ,form from the cement and from the collar and reinforcement,and withdrawing said form.

5. In a drilled well a hollow form, about which a cementitious substancemay be poured, a removable reinforcing collar about said form having anexternal configuration tapering inwardly from top to bottom andeffective to space the walls of said form. from the drilled bore of thewell, means to force a cementitious substance 40 between the walls ofsaid form and the walls of the drilled bore, and means to free said formfrom sticking to said cementitious substance.

6. The method of constructing wells which comprises coating a tubularform externally with a meltable substance which is hard at ordinarytemperatures, drilling a well bore, positioning said form within saidbore and in spaced relation to the walls thereof, forcing a cementitioussubstance into the space between said form and walls, applying heat tothe interior of said form to cure the cementitious substance and tomeltthe coating about the form whereby to release the form from thecementitious substance, and withdrawing the form.

7. The method of constructing wells which comprises coating a tubularform externally with a meltable substance which is hard at ordinarytemperatures, drilling a well bore, positioning said form within saidbore and in spaced relation to the walls thereof, forcing a cementitioussubstance into the space between said form and walls, applying heat tothe interior of said form to melt the coating about the form and tocause a permeation of the cementitious substance with the material ofsaid coating, and withdrawing said form after said coating has melted.

8. The method of constructing wells which comprises drilling a bore,inserting in said bore a hollow form having thereabout a reinforcingcollar shaped with an external configuration tapering inwardly from topto bottom and effective to space the walls of said form from the wallsof the drilled bore, forcing a cementitious substance between the wallsof said form and the walls of said bore, freeing said form from thecementitious substance, and withdrawing said form from the cementitioussubstance and reinforcing collar, thereby toleave said collar embeddedin the cementitious substance.

JACK W. ALLEN.

